Could this also mean that when the ignition switch is turned off some time has elapsed and the rotor land on the next cylinder which is No. 5 in this case.
Because I did check the wires #5 piston is on the driver side and that where # 5 wire on cap is going to the 1st piston on the driver side from front to back...
looking for SL Convertible/240 D/300 TD
420 SEL 1986
300 D 1978